Crosslinked and crosslinkable hollow fiber membrane and method of making same utility

• US 7,247,191 B2
• Filed: 06/10/2005
• Issued: 07/24/2007
• Est. Priority Date: 12/20/2001
• Status: Expired due to Term

• Current Assignee: Chevron USA Incorporated (Chevron Corp.)
• Original Assignee: Chevron USA Incorporated (Chevron Corp.)
• Inventors: Wallace, David, Miller, Stephen J., Koros, William J., Staudt-Bickel, Claudia, Wind, John
• Primary Examiner(s): Greene; Jason M.
• Application Number:
  US11/149,683
• Publication Number:
  US 20050268783A1
• Time in Patent Office: 774 Days
• Field of Search: 95/45, 95/51, 95/54, 96/4, 96/8, 96/10, 96/11, 96/12, 96/13, 96/14, 555/24, 55D/IG.5
• US Class Current: 96/13
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 2323/30 Cross-linking
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 65/109 Testing of membrane fouling or clogging, e.g. amount or affinity
• CPC Class Codes: B01D 67/00931 by introduction of specific groups after membrane formation, e.g. by grafting
• CPC Class Codes: B01D 67/00933 by addition of a layer chemically bonded to the membrane
• CPC Class Codes: B01D 69/08 Hollow fibre membranes manufacture of hollow fibres D01D5/24, D01F1/08
• CPC Class Codes: B01D 71/643 Polyether-imides
• CPC Class Codes: B01D 71/82 characterised by the presence of specified groups, e.g. introduced by chemical after-treatment
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y10S 55/05 Methods of making filter

Abstract

A composition of and a method of making high performance hollow fiber membranes is described. The membranes have a high resistance to plasticization by use of a predetermined amount of crosslinking. The preferred polymer material for the membrane is a polyimide polymer comprising covalently bonded ester crosslinks. The resultant hollow fiber membrane exhibits a high permeability of CO₂ in combination with a high CO₂/CH₄ selectivity. Another embodiment provides a method of making the hollow fiber membrane from a monesterified polymer followed by final crosslinking after hollow fiber formation.

Claims

1. A composite polymer membrane, comprising:

a crosslinked polyimide polymer having covalent ester crosslinks; and

having a CO₂ permeance of at least 20 GPU and a CO₂/CH₄ selectivity of greater than 20, at 35 degrees C. and a pressure of 100 psia.

12. The composite polymer membrane of claim 1 wherein the membrane is a flat sheet.

13. The composite polymer membrane of claim 12 wherein the membrane comprises a layer in a flat stack permeator.

14. The composite polymer membrane of claim 1 wherein the ester crosslinks are formed by the monoesterification of a polyimide polymer having carboxylic acid sites incorporated therein, with a diol.

15. The composite polymer membrane of claim 14 wherein the diol is selected from the group consisting of ethylene glycol, propylene glycol, 1,3 propanediol, 1,4 butanediol, 1,2 butanediol, benzenedimethanol, and 1,3 butanediol.

2. A composite polymer membrane, comprising:

a crosslinked polyimide polymer having at least some covalent ester crosslinks and having a ratio of crosslinkable sites to imide groups of between 3;

8 and 1;

16.

3. A composite polymer membrane, comprising:

a polyimide polymer made from the monomers A+B+C;

where A is a dianhydride of the formula;

where X₁ and X₂ are the same or different halogenated alkyl group, phenyl or halogen;

where R₁, R₂, R₃, R₄, R₅, and R₆ are H, alkyl, or halogen;

where B is a diamino cyclic compound without a carboxylic acid functionality;

where C is a diamino cyclic compound with a carboxylic acid functionality; and

wherein the ratio of B to C is between 1;

4 and 8;

1, and wherein said composite polymer membrane further comprises at least some covalent ester crosslinks.

4. The composite polymer membrane of claim 3 where X₁ and X₂ are CF₃.

5. The composite polymer membrane of claim 3 where R₁, R₂, R₃, R₄, R₅, and R₆ are H.

6. The composite polymer membrane of claim 3 wherein the dianhydnde is 6FDA.

7. he composite polymer membrane of claim 3 wherein C is DABA.

8. The composite polymer membrane of claim 3 wherein B is a diamino aromatic compound.

9. The composite polymer membrane of claim 3 wherein B is a methyl substituted diamino benzene.

10. The composite polymer membrane of claim 3 wherein the ratio of B to C is between 17:

3 and 3;

2.

11. The composite polymer membrane of claim 3 wherein said ester crosslinks are made using a diol selected from the group consisting of ethylene glycol, propylene glycol, 1,3 propanediol, 1,4 butanediol, 1,2 butanediol, benzenedimethanol, and 1,3 butanediol.

16. The composite polymer membrane of claim 3 wherein the ratio of B to C is between 4:

1 and 3;

2.

17. The composite polymer membrane of claim 3 wherein the polyimide polymer has an average molecular weight of between 20,000 and 200,000.

18. The composite polymer membrane of claim 3 wherein the membrane has an average molecular weight greater than the entanglement MW of the polymer.

19. The composite polymer membrane of claim 3 wherein the membrane has an average molecular weight of between 40,000 and 140,000.